$(document).ready(function () {
    MarginPages();    
    
    $(window).resize(function () {
        MarginPages();
    });
});



function MarginPages() {

    var altezza = $("#MasterMainContainer").innerHeight() - $("#MasterMainHeader").innerHeight();
    var diff = altezza - $("#MasterMainPages").innerHeight();
    $("#MasterMainPages").css("margin-top", ((diff / 2)) + "px");
}